The present invention relates to a transmission apparatus for motor vehicles in which the engine is longitudinally mounted in the front position of the vehicle and the output of the engine is transmitted to the front axle to drive the motor vehicle.
In recent years, there requirements have increased for the transmission to have a wide performance range. One of the requirements is that the motor vehicle can be economically driven at a high speed with low reduction ratio, and the other is that the vehicle can be powerfully driven under a heavy load condition with a higher reduction ratio than the conventional highest reduction rate.
Typical means for meeting such requirements is to increase the changing speed stages of the transmission in the number of the stages. However, this means results in complexity of manipulation for changing the speed of the transmission, thereby to decrease its practicability. In order to remove such disadvantages, it has been proposed to provide a sub-transmission together with the main transmission of which sub-transmission may be manipulated to change the transmission speed independent of the main transmission. If there is provided with a main transmission having a four-speed-stage and a sub-transmission having a two-speed-stage, the transmission having a eight-speed-stage may be obtained. Namely, when the sub-transmission is set in the lower speed stage, the main transmission can transmit four speeds in the lower speed range, and when the sub-transmission is set in the higher speed stage, four speeds in the higher speed range can be transmitted through the main transmission. In accordance with this sub-transmission apparatus, the manipulation is simply performed, because the main transmission may be manipulated in four stages. However, it is necessary to provide a special space in the transmission housing for the sub-transmission, which results in an increase of size of the transmission in dimensions, especially in length.
On the other hand, in the front wheel drive car, the engine should be mounted near the front axle for increasing the load on the front wheels to increase the gripping force of the front wheel against the ground.
If the long transmission is longitudinally mounted in the front position of the car, the engine must be extended forward from the front wheels more than the conventional car or the transmission must be positioned rearwardly whereby the space for the driver in the car is reduced. If the length from the front wheels to the front end of the car becomes long, it will become difficult to manipulate the steering wheel of the car.
Further, in the case that the sub-transmission is provided to transmit the output of the main transmission, the sub-transmission must be designed to have great dimensional size. If the inertia lock type synchromesh mechanism is employed in such a sub-transmission, inertia mass of the synchronized members in the mechanism will be great value, which makes the manipulation of the sub-transmission heavy.
Therefore, it is the object of the present invention to provide a transmission apparatus which need not provide a special space for the sub-transmission in the transmission housing, which may be manufactured in small size, and which sub-transmission may be easily manipulated.